1. Field of the Invention
The present invention relates to liquid containers and particularly to a liquid container for supplying ink to an inkjet recording head of an inkjet recording apparatus.
2. Description of the Related Art
Replaceable ink tanks are conventionally used as ink tanks for inkjet printers. Such a replaceable ink tank has a problem in that while the tank is being replaced, ink leaks out of the tank toward a joint where the tank is attached to the printer and, for example, makes the user's hands dirty or drips onto the printer main body.
FIG. 16 illustrates an exemplary configuration of an ink tank disclosed in Japanese Patent Laid-Open No. 09-300646 (corresponding to U.S. Pat. No. 6,082,852). An ink tank T2000 includes a main ink reservoir T2003 and an intermediary reservoir T2006 under the main ink reservoir T2003. A capillary member T2004 inside the main ink reservoir T2003 holds ink and maintains a negative pressure therein. The intermediary reservoir T2006 is provided with an ink supply port T2002 at the bottom to which a recording head is to be connected. The ink supply port T2002 is provided with a meniscus forming member (filter) T2009.
FIG. 17 is a cross-sectional view illustrating an exemplary configuration of an ink tank for pigment ink disclosed in Japanese Patent Laid-Open No. 2003-080730 (corresponding to U.S. Pat. No. 6,722,762).
To ensure a uniform concentration of ink inside the tank where a concentration gradient often occurs, an ink reservoir T2001, an ink channel T2014, and an ink supply port T2002 of the ink tank are arranged to form a complex structure. The ink supply port T2002 is provided with a ball valve, with which the ink reservoir T2001 is closed.
FIG. 18 illustrates an exemplary configuration of an ink tank disclosed in Japanese Patent Laid-Open No. 08-216424 (corresponding to U.S. Pat. No. 6,000,790). Unlike the intermediary reservoir T2006 illustrated in FIG. 16, an intermediary reservoir T2006 in FIG. 18 has the form of a narrow channel and is provided with an ink supply port T2002 at an end thereof.
FIG. 19 illustrates an exemplary configuration of an ink tank disclosed in Japanese Patent Laid-Open No. 2005-067075. An intermediary reservoir T2006 having the form of a narrow channel is provided with an ink supply port T2002 at a bottom end thereof. The intermediary reservoir T2006 communicates with a main ink reservoir T2003 through an opening T2014.
In the ink tank T2000 illustrated in FIG. 16, the intermediary reservoir T2006 filled with ink is disposed over the meniscus forming member T2009 for the ink supply port T2002. Therefore, external shocks applied to the ink tank T2000 when it is dropped may cause the ink inside the intermediary reservoir T2006 to break a meniscus formed at the meniscus forming member T2009 and further, to spatter from inside the ink tank T2000 to the outside.
In the ink tank illustrated in FIG. 17, the ball valve for the ink supply port T2002 can prevent ink from spattering. However, the ink tank, which is closed with the ball valve, suffers the disadvantages of having a complicated structure and the reduced amount of ink that can be stored in the ink tank.
Like the ink tank illustrated in FIG. 16, the ink tank in either FIG. 18 or FIG. 19 is configured such that the intermediary reservoir T2006, which is filled with ink, extends toward the ink supply port T2002. Therefore, if, for example, the ink tank T2000 is dropped and subjected to external shocks, the pressure of the ink may be easily and directly transmitted to the ink supply port T2002. This may cause a meniscus at the meniscus forming member to be broken and the ink to spatter.